Don't try to support allocs > 2GB

syzygy/agent/asan/heap_managers/block_heap_manager.cc

 // Copyright 2014 Google Inc. All Rights Reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 218 matching lines @@
         bytes,
         0,
         parameters_.trailer_padding_size + sizeof(BlockTrailer),
         &block_layout);
     if (alloc != nullptr) {
       heap_id = heaps[i];
       break;
     }
   }
 
-  // The allocation might fail because its size exceed the maximum size that
-  // we can represent in the BlockHeader structure, try to do an unguarded
-  // allocation.
+  // The allocation can fail if we're out of memory or if the size exceed the
+  // maximum allocation size.
   if (alloc == nullptr)
-    return DoUnguardedAllocation(GetHeapFromId(heap_id), shadow_, bytes);
+    return nullptr;
 
   DCHECK_NE(static_cast<void*>(nullptr), alloc);
   DCHECK_EQ(0u, reinterpret_cast<size_t>(alloc) % kShadowRatio);
   BlockInfo block = {};
   BlockInitialize(block_layout, alloc, &block);
 
   // Poison the redzones in the shadow memory as early as possible.
   shadow_->PoisonAllocatedBlock(block);
 
   block.header->alloc_stack = stack_cache_->SaveStackTrace(stack);
@@ skipping 870 matching lines @@
   if (trailer_has_valid_heap_id)
     return block_info->trailer->heap_id;
 
   // Unfortunately, there's no way to know which heap this block belongs to.
   return 0;
 }
 
 }  // namespace heap_managers
 }  // namespace asan
 }  // namespace agent